The present invention relates generally to the field of data access and interaction, and more particularly to the analysis and visualization of multidimensional datasets.
The need for organizing large bodies of data has lead to the development of many types of data management systems, ranging from simple files to relational databases. Although these systems provide suitable storage and query features, they are not very well suited for exploratory analysis, and using them requires a non-trivial degree of technical expertise.
In response to this problem, the field of On-line Analytical Processing (OLAP) has emerged. The basic premise of OLAP is that end users think of their data in terms of a number of dimensions and would like to be able to explore the data by manipulating these dimensions in a number of ways. For example, a business manager may think in terms of Products, Channels, Regions, Years, and so on. He may then want to perform operations such as rearranging views using different dimensions, slicing and dicing the data along various dimensions, drilling down into subgroups within a dimension, or rolling up subgroups into aggregate totals. An OLAP server allows users to perform these operations on data accessed from relational databases. Typically, a spreadsheet provides users an exploratory environment for visualization for slices of data. A number of quite powerful front-end tools suited to this kind of exploration of multidimensional data have been developed. However, these tools are still largely based on textual views and don""t leverage powerful human perceptual abilities that could support exploration.
U.S. Pat. No. 5,632,009 to Rao et al., which is hereby incorporated by reference, describes a tool that allows users to view multivariate datasets (i.e., datasets having two dimensions, one dimension of variables and the second of cases associated with the variables) using a mixed graphical/textual representation of the data. This xe2x80x9cfocus+contextxe2x80x9d technique allows for the visualization and manipulation of large two-dimensional tables (roughly 30-100 times as big in the same screen space as a conventional spreadsheet or table browser). Because it displays much more of the table at once by using graphics to show values, a user can examine patterns in the whole table as well as zoom in on specific content without losing global context.
Although the focus+context technique, as described in the Rao patent, is a powerful tool for viewing and manipulating multivariate data, it does not allow for effective interaction and manipulation of multidimensional data. There is, therefore, a need in the art to provide efficient analysis and visualization of multidimensional data, such as the data manipulated by OLAP systems.
Objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
To achieve the objects and in accordance with the purpose of the invention, as embodied and broadly described herein, a first aspect consistent with the present invention includes a method of visualizing a multidimensional data set. The method includes the steps of (1) storing the multidimensional data set using an abstract data model partitioned into dimensions; (2) converting portions of the data set stored in the abstract data model into a visual model having dimensions of the abstract data model organized as at least one hierarchical tree; and (3) displaying the visual model to a user as a tabular representation on a computer display screen, wherein a first portion of the data of the data set is displayed in a first level of detail in the tabular representation and a second portion of the data in the data set is displayed in a second level of detail in the tabular representation, the first level of detail using more screen space per data value than the second level of detail.
A second aspect of the present invention is directed to a computer system comprising a processor, a display, and a memory. The memory includes computer instructions and computer data, the computer instructions when executed on the processor causing the processor to perform the functions of: (1) storing the multidimensional data set using an abstract data model partitioned into dimensions; (2) converting portions of the data set stored in the abstract data model into a visual model having dimensions of the abstract data model organized as at least one hierarchical tree; and (3) displaying the visual model to a user as a table in which a first portion of the data in the table is displayed in a first level of detail and a second portion of the data in the table is displayed in a second level of detail, the first level of detail using more screen space per data value than the second level of detail.
A third aspect of the present invention is directed to a method of invoking an operation on a data set having three or more dimensions comprising the steps of: (1) converting portions of the data set into a two-dimensional visual model; (2) displaying the visual model on a physical medium; (3) detecting a user""s interaction with the data represented in the visual model; (4) initiating an operation on the data set based on the detected user interaction with the data; and (5) updating the visual model to reflect the operation initiated by the user.